If you don't operate a website, you can view the real-time moon module anytime from your computer by bookmarking the Current Moon Phase Page (link opens a new window; after it opens, bookmark the page using your web browser). Or you can add it to your Google home page.

The free moon module shown above is pretty useful. But if you'd like additional features like monthly calendars, upcoming full moon / new moon info, and other details, download a copy of QuickPhase for use anytime on your personal computer.

I created it, so I couldn't be biased :-) ... but it's a big time-saver if you're looking at the moon phases regularly. Plus it's attractive. Most other moon phases calendar applications are either unwieldy, ugly, complicated, or inconvenient because you have to access a website to use it. As I've used it, I found an unexpected side benefit -- a handy general purpose calendar for looking at future dates, since it seems like I never have a wall calendar.

Here are a few core features:

detail on current moon phases, like full moon percentage, when the next new or full moon is, etc

thousands of years of past and future moon phases calendars, so you can:

The phases of the moon are caused by the relative positions of the earth, sun, and moon. The moon goes around the earth in 27.3 days, or 27 days 7 hours 43 minutes, on average. This measurement is relative to the stars and is called the sidereal period or orbital period. However, because of the earth's motion around the sun, a complete moon cycle (New Moon to New Moon) appears to earthbound observers to take a couple of days longer: 29.5305882 days to be exact. This number is called the synodic period or "lunation", and is relative to the sun.

The sun always illuminates the half of the moon facing the sun (except during lunar eclipses, when the moon passes through the earth's shadow). When the sun and moon are on opposite sides of the earth, the moon appears "full" to us, a bright, round disk. When the moon is between the earth and the sun, it appears dark, a "new" moon. In between, the moon's illuminated surface appears to grow (wax) to full, then decreases (wanes) to the next new moon. The edge of the shadow (the terminator) is always curved, being an oblique view of a circle, giving the moon its familiar crescent shape.

moon pictures - very interesting lunar images! This NASA page has over 130 pictures (thumbnails) of the moon. Click on a thumbnail to for more info. Close-ups of the surface of the moon, distance views, astronauts, moon landings, more.

K-12 lunar phases activity from NASA - rather than use chalkboard diagrams to illustrate the phases, this activity uses actual objects (pencil, styrofoam ball) to help students grasp the concepts; Newton's Apple has a similar but more detailed moon phase lesson plan for elementary-age students

phases of the moon online movie - this is a short movie taught by a Newton's Apple scientist and a professional astronomer in an interesting, conversational manner, using large 3-D moon and earth spheres and simulated sunlight to demonstrate how the moon phases work

Earth-Moon-Sun system video diagrams - from NOAO (National Optical Astronomy Observatory), these QuickTime online video clips and animations are an excellent way to illustrate the moon's phases

There are many theories and thoughts about the effects of the moon on people, animals, and the natural world. Here are a few interesting links:

moon and the tides - this is a concise page on how the moon affects the tides by its phase (full moon, new moon, etc) and its position (perigee, apogee)